The graphic novel will focus on the mystery of Fire Lord Zuko's mother's disappearance.

"Like every other Airbender fan out there, I gasped at the end of that scene in the last episode, where Zuko confronts [his father] Ozai," Yang told Comic Book Resources.

"How could [they] just leave us hanging like that?! In the last episode, with no immediate plans for resolution! And now, for me to have a hand in answering some of those questions - like I said, surreal."

"The Search focuses on Zuko and [his sister] Azula," he continued. "Aang, Katara and Sokka will be there, of course, but the Fire Nation royal siblings are really the drivers of the action.

"In The Promise, we see Zuko struggling with his responsibilities as Fire Lord. The Search is the next stage of that struggle."

Avatar: The Last Airbender - The Search will be released following the debut of the third and final volume of The Promise in September.